Abstract: OBJECTIVE To analyze the influence of ulinastatin to Th1/Th2 of peripheral blood of patients with severe sepsis, so as to provide evidence for the completing of its anti-inflammatory mechanism. METHODS A total of 93 patients with severe sepsis accepted from Sep. 2014 to Oct. 2015 were selected and randomly divided into 2 groups, including 46 cases of conservative therapy group and 47 cases of ulinastatin group. Patients in conservative therapy group were given comprehensive therapy, while patients in ulinastatin group were given ulinastatin on the base of comprehensive therapy (300, 000U, q8h, for 5 days). The fasting venous blood before and after treatment was extracted to detect the Th1 and Th2 cell percentage by flow cytometry, and the serum levels of IL-2 and IL-10 were detected by ELISA kits. A total of 33 cases of volunteers were selected as control group, and compared with other groups. RESULTS Before treatment, the Th1 and Th2 cell percentage, and the serum levels of IL-2 and IL-10 of patients of conservative therapy group were all higher than those of control group, while Th1/Th2 and IL-2/IL-10 were both lower than those of control group (P<0.05); but there was no significant difference between conservative therapy group and ulinastatin group. After treatment, the Th1 and Th2 cell percentage, and the serum levels of IL-2 and IL-10 of ulinastatin group were all lower than those of conservative therapy group, while Th1/Th2 and IL-2/IL-10 were both higher than those of conservative therapy group (P<0.05). CONCLUSION Ulinastatin has ability to approve the Th1/Th2 drifting of patients with severe sepsis, which is benefit to maintain pro-inflammatory/anti-inflammatory steady state and improve the condition of patients.